On Wed, Feb 19, 2025 at 09:48:49PM +0200, Niko Tyni wrote: > On Wed, Feb 19, 2025 at 08:51:47AM +0100, Sebastiaan Couwenberg wrote: > > Discussion with upstream suggests that perl, pdl, and libpdl-io-hdf5-perl > > need to be built with the same GCC version to resolve this issue. > > AFAIK this has not been a requirement with earlier GCC upgrades, and it > seems rather onerous. I'm not at all sure how the relevant dependencies > should look like. > > I think we need to understand properly why Perl thinks the XS ABI is > different when modules are built with GCC 15 vs. 14, and whether this > is somehow specific to the PDL ecosystem or a wider issue.
This is specific to libpdl-io-hdf5-perl and libpdl-netcdf-perl, not a wider issue. It is caused by them adding -Dbool=int to the build flags. I doubt it would work even if perl, pdl, and libpdl-io-hdf5-perl were all built with GCC 15 (but I didn't bother to try.) The Perl headers #include <stdbool.h> if available, which is the case on Debian. This system header #defines bool only on C17 and lower, as it has become a keyword of its own on C23. GCC 15 changes the default C language version from C17 to C23. The combined effect is that for C17 (gcc -std=gnu17, default on GCC 14) the stdbool.h definition overrides the -Dbool=int command line definition, rendering it harmless (if nonsensical). But for C23 (gcc -std=gnu23, default on GCC 15) -Dbool=int actually changes the bool size, breaking the XS module interface. My suggestion is to remove the -Dbool=int fiddling from the respective Makefile.PL files, at least on Debian. The PDL-NetCDF git history suggests that it was added to fix a build problem on Red Hat Linux 5.2 with perl 5.00404, so presumably 1998 or so. Hope this helps, -- Niko
